Benedict Cumberbatch made an appearance this week on Late Night With Jimmy Fallon to promote his latest film The Fifth Estate. While on the program, host Jimmy Fallon challenged the Star Trek Into Darkness star to an “Alan Rickman-off,” since the two of them apparently can do impersonations of the Harry Potter actor (who plays the wicked Severus Snape in the film franchise).

The catch is that they have to sound like Rickman while reciting popular hip hop lyrics.